EP 2 289 659 A1 discloses a friction-welding member having a head and a shaft, with a drive being formed in the head. The head has a flat surface which is suitable for transmitting the axial force. The head furthermore has a recess formed in its underside, which recess is adapted to accommodate any material softened during the friction-welding process, in particular material from the top layer.
The shaft of the connecting element is friction-welded to the lower base layer of the composite component. The projecting length of the head ensures a positive connection between the base and top layers. The base and top layers are thus firmly connected to each other by means of the connecting element.
A setting tool is provided for producing the friction-welding connection, which tool comprises a hold-down device and a drive tool. The hold-down device presses the component layers to be connected onto each other, while the drive tool presses down on and rotates the connecting element, thus driving it into the composite component.
This design has the disadvantage that it has to be of a high overall height and small in diameter.